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Order Ceramiales

Family Rhodomelaceae

Laurencia flexuosa (Suhr) Kützing 1849: 856

Plants bright red to brownish-red or purplish-red, one to several erect axes arising from a common holdfast, up to 40 cm tall. Plants complanate, branching irregularly alternate, main axis flexuous; older plants with several orders of branches, not crowded except when fertile. Axes compressed, 2-3 mm wide and about half as thick. In cross section central and pericentral cells not distinguishable. Medulla of isodiametric, rather thin-walled cells; no special cell-wall thickenings present; outer cortical cells wider than deep, in surface view about isodiametric, with secondary pit-connections in the longitudinal direction. Outermost cotical cells with 1-3 corps en cerise. Reproductive plants with clusters of crowded terminal branchlets.

Collections, ecology and regional distribution

Recorded from False Bay eastwards to Mabibi in northern KwaZulu-Natal (45-57). On wave-exposed shores, from the lower eulittoral zone to shallow sublittoral.

Word distribution: Also reported from Mozambique (De Clerck et al. 2005).

Type locality: “Cape of Good Hope”, South Africa (De Clerck et al. 2005).

Note: Easily confused with L. alfredensis, but the latter species has 5-6 corps en cerise in the outer cortical cells and is more regularly branched. Prior to the DNA study of South African Laurencia (Francis et al. 2017), which described L. alfredensis, entities of both species would have been identified as L. flexuosa.

 

Laurencia flexuosa, Tsitsikamma.

Laurencia flexuosa, Tsitsikamma; shorter, denser plants.

Laurencia flexuosa, detail. White spots near apices show where tetrasporangia were shed.

Laurencia flexuosa, surface view of outer cortical cells, each with 1-3 corps en cerise.

 

References Laurencia flexuosa

De Clerck, O., Tronchin, E. M., & Schils, T. 2005. Red algae. In: De Clerck, O., J.J. Bolton, R. J. Anderson and E. Coppejans, 2005. Guide to the Seaweeds of Kwazulu-Natal. National Botanic Garden of Belgium, Brussels (Scripta Botanica Belgica), pp. 130-269.

Francis, C.M., Bolton, J.J., Mattio, L., Mandiwana-Neudani, T. & Anderson, R.J. 2017. Molecular systematics reveals increased diversity within the South African Laurencia complex (Rhodomelaceae, Rhodophyta). Journal of Phycology 53: 804-819.

Kützing, F.T. (1849). Species algarum. pp. [i]-vi, [1]-922. Lipsiae [Leipzig]: F.A. Brockhaus.

Stegenga, H., Bolton, J.J. & Anderson, R.J. 1997. Seaweeds of the South African west coast. Contributions from the Bolus Herbarium 18: 655 pp.

 

Cite this record as:

Anderson RJ, Stegenga H, Bolton JJ. 2016. Seaweeds of the South African South Coast.
World Wide Web electronic publication, University of Cape Town, http://southafrseaweeds.uct.ac.za; Accessed on 18 December 2018.